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Classically hard to simulate quantum states, or "magic states", are prerequisites to quantum advantage, highlighting an apparent separation between classically and quantumly tractable problems. Classically simulable states such as Clifford…

Quantum Physics · Physics 2025-01-13 Luke Coffman , Graeme Smith , Xun Gao

Remarkable efforts in the study of the semi-classical regime of kinematical loop quantum gravity are currently underway. In this note, we construct a ``quasi-coherent'' weave state using Gaussian factors. In a similar fashion to some other…

General Relativity and Quantum Cosmology · Physics 2009-10-31 A. Corichi , J. M. Reyes

Squeezed states of the harmonic oscillator are a common resource in applications of quantum technology. If the noise is suppressed in a nonlinear combination of quadrature operators below threshold for all possible up-to-quadratic…

Quantum Physics · Physics 2023-06-13 Vojtěch Kala , Petr Marek , Radim Filip

We numerically solve the effective loop quantum cosmology dynamics for the vacuum Bianchi type II and type IX spacetimes, in particular studying how the Kasner exponents evolve across the loop quantum cosmology bounce. We find that when the…

General Relativity and Quantum Cosmology · Physics 2023-10-11 Timothy Blackmore , Edward Wilson-Ewing

Recent advances in quantum technologies have enabled quantum simulation of gauge theories -- some of the most fundamental frameworks of nature -- in regimes far from equilibrium, where classical computation is severely limited. These…

Quantum Physics · Physics 2025-09-05 Jad C. Halimeh , Niklas Mueller , Johannes Knolle , Zlatko Papić , Zohreh Davoudi

We study the evolution of the hybrid entangled squeezed states of the qubit-oscillator system in the strong coupling domain. Following the adiabatic approximation we obtain the reduced density matrices of the qubit and the oscillator…

Quantum Physics · Physics 2016-10-18 M. Balamurugan , R. Chakrabarti , B. Virgin Jenisha

We analyze the semiclassical polymer dynamics of the inhomogeneous Mixmaster model by choosing the cubed scale factor as the discretized configurational variable, while the anisotropies remain pure Einsteinian variables. Such a modified…

General Relativity and Quantum Cosmology · Physics 2019-02-06 Stefano Antonini , Giovanni Montani

We investigate the quantum irreversibility and quantum diffusion in a non-Hermitian kicked rotor model for which the kicking strength is complex. Our results show that the exponential decay of Loschmidt echo gradually disappears with…

Quantum Physics · Physics 2022-11-29 Wen-Lei Zhao , Huiqian Zhang

An improved Hamiltonian constraint operator is introduced in loop quantum cosmology. Quantum dynamics of the spatially flat, isotropic model with a massless scalar field is then studied in detail using analytical and numerical methods. The…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Abhay Ashtekar , Tomasz Pawlowski , Parampreet Singh

Inhomogeneous quantum cosmology is modeled as a dynamical system of discrete patches, whose interacting many-body equations can be mapped to a non-linear minisuperspace equation by methods analogous to Bose-Einstein condensation.…

General Relativity and Quantum Cosmology · Physics 2012-12-18 Martin Bojowald , Alexander L. Chinchilli , Christine C. Dantas , Matthew Jaffe , David Simpson

We investigate two simplified non-singular cyclic models with a negative time-varying cosmological constant to represent the non-conventional mechanism of negative cosmological constant expected to address the late-time cosmic acceleration.…

General Relativity and Quantum Cosmology · Physics 2026-05-21 Nasr Ahmed , Kazuharu Bamba

We show that the quantum evolution of a spin-1 Bose gas with nearly all bosons initially in the $F_z = 0$ state has a "quantum carpet" {\em spin-time} structure with self-similar properties. The system continuously evolves into…

Other Condensed Matter · Physics 2007-05-23 Roberto B. Diener , Tin-Lun Ho

Structure in the Universe is widely believed to have originated from quantum fluctuations during an early epoch of accelerated expansion. Yet, the patterns we observe today do not distinguish between quantum or classical primordial…

High Energy Physics - Theory · Physics 2020-07-01 Daniel Green , Rafael A. Porto

Closed, singularity-free, inflationary cosmological models have recently been studied in the context of general relativity. Despite their appeal, these so called emergent models suffer from a number of limitations. These include the fact…

Astrophysics · Physics 2009-11-10 David J. Mulryne , Reza Tavakol , James E. Lidsey , George F. R. Ellis

We present a detailed analysis of a quantum model for Loop Quantum Cosmology based on strict application of the Thiemann regularization algorithm for the Hamiltonian in Loop Quantum Gravity, extending the results presented previously in our…

General Relativity and Quantum Cosmology · Physics 2019-10-09 Mehdi Assanioussi , Andrea Dapor , Klaus Liegener , Tomasz Pawlowski

Bounce cosmological models containing a dark viscous fluid in a spatially flat Friedmann-Robertson-Walker (FRW) universe are considered. The universe evolution is described in terms of generalized equation of state (EoS) parameters, in…

General Relativity and Quantum Cosmology · Physics 2024-11-19 E. Elizalde , A. V. Yurov , A. V. Timoshkin

When quantum back-reaction by fluctuations, correlations and higher moments of a state becomes strong, semiclassical quantum mechanics resembles a dynamical system with a high-dimensional phase space. Here, systematic computational methods…

General Relativity and Quantum Cosmology · Physics 2011-09-13 Martin Bojowald , David Brizuela , Hector H. Hernandez , Michael J. Koop , Hugo A. Morales-Tecotl

We consider quantum (unitary) continuous time evolution of spins on a lattice together with quantum evolution of the lattice itself. In physics such evolution was discussed in connection with quantum gravity. It is also related to what is…

Mathematical Physics · Physics 2015-06-26 V. A. Malyshev

A research program within the scope of theories on "Emergent Quantum Mechanics" is presented, which has gained some momentum in recent years. Via the modeling of a quantum system as a non-equilibrium steady-state maintained by a permanent…

Quantum Physics · Physics 2015-01-14 Gerhard Groessing

A brief review of the modern state of quantum cosmology is presented as a theory of quantum initial conditions for inflationary scenario. The no-boundary and tunneling states of the Universe are discussed as a possible source of probability…

General Relativity and Quantum Cosmology · Physics 2017-08-23 A. O. Barvinsky